There are two main attractions at Azraq. The first is the fort, one of the desert castles. Unlike Kharaneh and Qasr Amra, Azraq actually served a defensive purpose. It was probably originally built by the Romans, and then rebuilt by successive occupiers of the land. The current form owes much to the Ayyubid dynasty who built the distinctive black basalt walls. The fort was later occupied by the Ottomans, and was then used as a headquarters by T.E. Lawrence as he built up his force of Arab irregulars during The Great War (his office was directly above the gatehouse). The fort is in good condition, and some of the rooms contain rescued carvings and friezes. The reason for the fort's existence is the nearby spring. Now a shadow of its former self, this spring once fed a huge marshland that was a critical habitat for millions of migrating birds, as well as home to herds of water buffalo. Sadly the spring has nearly dried up as Amman expands to consume ever more water, but there is still a small body of water and towering reed beds, a small herd of buffalo and a few migrating birds: it's worth visiting just to get a sense of what the desert can be like if there is some water around.